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The CuOFP capsule used as overpack for spent nuclear fuel disposal in the KBS-3 concept (Swedish version). Oxygen-free copper (OFC) or oxygen-free high thermal conductivity (OFHC) copper is a group of wrought high-conductivity copper alloys that have been electrolytically refined to reduce the level of oxygen to 0.001% or below.
The abundance of elements in Earth's crust is shown in tabulated form with the estimated crustal abundance for each chemical element shown as mg/kg, or parts per million (ppm) by mass (10,000 ppm = 1%).
Almost never found free in nature, it is very low in abundance, composing only 0.001% (10 ppm) [41] of the Earth's crust. It is known to occur in over a hundred different minerals and ores , however: the main source is borax , but it is also found in colemanite , boracite , kernite , tusionite , berborite and fluoborite . [ 42 ]
Manganese comprises about 1000 ppm (0.1%) of the Earth's crust and is the 12th most abundant element. [71] Soil contains 7–9000 ppm of manganese with an average of 440 ppm. [71] The atmosphere contains 0.01 μg/m 3. [71]
Nearly all plants, even those somewhat tolerant of soil boron, will show at least some symptoms of boron toxicity when soil boron content is greater than 1.8 ppm. When this content exceeds 2.0 ppm, few plants will perform well and some may not survive. [161] [162] [163] Some boron-containing antibiotics exist in nature. [164]
A related concept is one part per ten thousand, 1 / 10,000 .The same unit is also (rarely) called a permyriad, literally meaning "for (every) myriad (ten thousand)". [4] [5] If used interchangeably with basis point, the permyriad is potentially confusing because an increase of one basis point to a 10 basis point value is generally understood to mean an increase to 11 basis points; not ...
Potassium-40 (40 K) is a long lived and the main naturally occurring radioactive isotope of potassium.Its half-life is 1.25 billion years. It makes up about 0.012% (120 ppm) of natural potassium.
Example: copper in terrestrial sources. Two isotopes are present: copper-63 (62.9) and copper-65 (64.9), in abundances 69% + 31%. The standard atomic weight (A r °(Cu)) for copper is the average, weighted by their natural abundance, and then divided by the atomic mass constant m u.